1. Technical Field
The present invention relates to a valve for controlling fluid flow in a hydraulic power assist steering gear assembly.
2. Description of the Prior Art
A known control valve for controlling fluid flow in a hydraulic power assist steering gear assembly includes a valve core rotatable within a valve sleeve. The valve core and the valve sleeve each have a plurality of lands and grooves. When the valve core and the valve sleeve are in a neutral or centered condition, fluid pressure in opposite chambers of a hydraulic motor are equal. When the valve core and the valve sleeve are relatively rotated from the neutral condition, the lands and grooves on the valve core and the valve sleeve cooperate to direct fluid under pressure to one chamber of the motor, thereby to provide steering assist.
The lands and grooves in the valve core and the valve sleeve define very small orifices through which fluid flows. Large pressure differentials at these orifices can generate undesirable noise in the steering system.